Inreasing the cationic dyeability of acrylic shaped articles

ABSTRACT

AN IMPROVED DYEBATH COMPOSITION AND AN IMPROVED PROCESS FOR DYEING AN ACRYLIC SHAPED ARTICLE (E.G., FIBER OR FILM) ARE DISCLOSED. THE SHAPED ARTICLE IS CONTACTED WITH AN AQUEOUS DYEBATH COMPOSITION OF A CATIONIC DYE CONTAINING A MINOR QUANTITY OF METHYL CYANIDE SUFFICIENT TO PROMOTE THE DYEING OF AN ACRYLIC FIBROUS MATERIAL.

3,759,665 INCREASING THE CATIONlIC DYEABILITY F ACRYLIC SHAPED ARTICLES Alex S. Forschirm, Hiawatha, N.J., assignor to Celanese Corporation, New York, NY. No Drawing. Filed Oct. 14, 1971, Ser. No. 189,366 Int. Cl. 1306p 1/86, 3/76 U.S. Cl. 8-172 8 Claims ABSTRACT OF THE DISCLOSURE An improved dyebath composition and an improved process for dyeing an acrylic shaped article (e.g., fiber or film) are disclosed. The shaped article is contacted with an aqueous dyebath composition of a cationic dye containing a minor quantity of methyl cyanide sufficient to promote the dyeing of an acrylic fibrous material.

BACKGROUND OF THE INVENTION This invention relates to a composition suitable for dyeing an acrylic shaped article. In particular, this invention relates to a dyestutf composition for dyeing an acrylic shaped article, e.g., fiber, film, etc., which contains a cationic dye and a dye promoter. This invention further relates to an improved method for dyeing acrylic shaped articles with a cationic dye. Acrylic shaped articles, as discussed hereinbelow, refer to acrylic shaped articles having acidic sites and dyeable with cationic dyes.

The utilization of a cationic or basic dye in the dyeing of an acrylic shaped article such as a fiber is generally known. Conventionally, dyeing of acrylic fibers includes contact with a cationic dye-containing dyebath at a pH less than about 7 for about 1 to 3 hours at a temperature of about 100 C. The dyebath often contains auxiliary agents as known to those skilled in the art. Also, the rate of heating the dyebath to the dyeing temperature is carefully controlled.

Dyeing of acrylic fibers with cationic dyes is not without problems. For example, carriers or promoters are often added to dyebaths containing cationic dyes to prevent shrinkage of the acrylic fiber while it is being dyed and also to improve the uptake of the dye intothe fiber.

It is disclosed in U.S. Pat. No. 3,493,981 that certain aromatic compounds containing varying functional groups directly attached thereto are effective carriers for dyeing acrylic fibers. Benzonitrile is disclosed as such an effective carrier. Other aromatic nitriles are disclosed to be less efficacious than benzonitrile. U.S. Pat. No. 3,114,588 discloses a dyeing assistant or carrier for dyeing hydrophobic fibers which is an aryloxy propionitrile compound such as phenoxy propionitrile.

These carriers or dyeing assistant compounds, while they may assist dyeing of acrylic or hydrophobic fibers, require the use of an emulsifying and/or dispersing agent to disperse the compounds throughout the dyebath. The addition of emulsifying and/or dispersing agents necessarily adds another extraneous material to the dyebath which can have a detrimental effect on the dyeing opera tion. For example, as noted in U.S. Pat. No. 3,114,588, too high a proportion of emulsifier interferes with the fixation of the dyestuif onto the fiber.

It is an object of this invention to provide an improved aqueous cationic dye-containing dyestuff composition suitable for dyeing acrylic shaped articles, which dyestutf composition includes a water-soluble dyeing assistant.

It is an object of this invention to provide an improved dyebath composition which does not require the use of an emulsifying and/ or dispersing agent.

It is an object of this invention to provide an improved dyebath composition which is both relatively inexpensive and easy to handle.

hired States Patent Oifice Patented Sept. 18, 1973 It is an object of this invention to provide an aqueous cationic dye-containing dyestufi. composition which provides an improved dye uptake including both speed and amount of dye uptake when applied to acrylic shaped articles.

It is a further object of this invention to provide a method for dyeing an acrylic shaped article utilizing an aqueous dyebath composition containing a water-soluble dyeing assistant.

SUMMARY OF THE INVENTION These and other objects of the invention are achieved by providing an improved dyestuff composition for dyeing an acrylic shaped article comprising:

(a) an aqueous dyebath of a cationic dye, and (b) a minor quantity of methyl cyanide sufiicient to promote the dyeing of an acrylic shaped article.

In another aspect, the invention provides an improved process for dyeing an acrylic shaped article which comprises contacting the article to be dyed with an aqueous dyebath comprising:

(a) a cationic dye, and (b) a minor quantity of methyl cyanide sufficient to promote the dyeing of the acrylic shaped article.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The acrylic shaped articles, e.g., fibers or films or the like, undergoing dyeing in the present invention are generally known in the art. These acrylic materials, and particularly polyacrylom'trile, one of the most important polymeric acrylic materials, may be formed by conventional solution spinning techniques (i.e., may be dry spun or wet spun) or by conventional solvent casting techniques, and are commonly drawn to increase their orientation. As is known in the art, dry spinning is commonly conducted by dissolving the polymer in an appropriate solvent, such as N,N'-dimethylformamide or N,N'-dimethylacetamide, and passing the solution through an opening of predetermined shape into an evaporative atmosphere (e.g., nitrogen) in which much of the solvent is evaporated. Wet spinning is commonly conducted by passing a solution of the polymer through an opening of predetermined shape into an aqueous coagulation bath. Casting is commonly conducted by placing a solution containing the polymer upon a support, and evaporating the solvent therefrom.

The acrylic polymer utilized as the starting material is preferably formed primarily of recurring acrylonitrile units. For instance, the acrylic polymer should preferably contain not less than about mol percent of acrylonitrile units and not more than about 15 mol percent of units derived from a monovinyl compound which is copolymerizable with acrylonitrile such as styrene, methyl acrylate, methyl methacrylate, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl pyridine, and the like, or a plurality of such monomers. The acrylic polymer utilized as the starting material may also be a modacrylic polymer, i.e., a long chain polymer containing less than 85 mol percent but more than 35 mol percent of acrylonitrile units. The term acrylic shaped article as used herein is meant to include modacrylic shaped articles also.

The acrylic shaped article is preferably provided as a continuous length of a fibrous material and may be in a variety of physical configurations. For instance, the acrylic fibrous material may be present in the form of continuous lengths of multifilament yarns, tows, tapes, strands, cables, or similar fibrous assemblages. Alternatively, acrylic films of relatively thin thickness, e.g., about 1 to 10 mils, may be dyed.

When the starting material is a continuous multifilament yarn, a twist may be imparted to the same, as known in the art, to improve the handling characteristics. The starting material may also be drawn in accordance with conventional techniques in order to improve its orientation. The starting material may also be secured, bleached or otherwise physically or chemically treated in a known manner prior to dyeing.

The acrylic shaped articles have acidic sites which attract cationic dyes. The acrylic shaped articles may, for example, include acid-modified acrylic material and acrylic materials containing acid residues such as known in the art.

The aqueous dyebath with the exception of the methyl cyanide may be formed in a conventional manner containing the cationic dye, pH regulators, etc., as will be apparent to those skilled in the art.

The cationic dyes utlized in the dyestufl? composition of this invention can be any of the known cationic or basic dyes suitable for dyeing an acrylic article. Suitable basic dyes include the diphenylmethane and tripheuylmethane derivatives, rhodamine dyes, azo dyes, anthraquinone dyes, thiazine dyes, oxazine dyes, xanthene dyes, polymethine dyes, azomethine dyes, said cyanine dyes. Specifically, basic dyes which can be used in this invention include: diphenylmethanes (ketone imines) such as auramine; triarylmethane dyes such as Color Index (hereinafter C.I.) Basic Green 1, C.I. 42,040, fuchsine (C.I. 42,500), resorcine violet (C.I. 43,520) Victoria blue (C.I. 44,040), basic violet (C.I. 42,557) (Suppl), rhoduline violet (C.I. 44,520), the basic dyes of U.S. Pat. 3,021,344, U.S. Pat. 3,032,561 and U.S. Pat. 2,083,888; xanthene dyes such as Pyronine G (C.I. 45,005), methylene red (C.I. 45,006), Rhodamine (C.I. 45,050), saccharein (C.I. 45,070), Rhodamine 5G (C.I. 45,105), Rhodamine G (C.I. 45,150), Rhodamine 6G (C.I. 45,- 160), Rhodamine 12GM (C.I. 45,310); acridines such as Acridine Orange NO (C.I. 46,005), Diamond Phosphine GG (C.I. 46,035), Rheonine AL (C.I. 46,075); methine dyes such as basic red C.I. 48,015, basic red C.I. 48,013, basic violet C.I. 48,020, basic orange C.I. 48,035, basic yellow C.I. 48,055, basic red C.I. 48,070, basic yellow C.I. 48,060, basic yellow C.I. 48,065, basic dyes prepared from 2-methylene-1,3,3-trimethylindoline (Fischers Base) as disclosed in U.S. Pat. 2,734,901 and in Synthetic Dyes by Venkataraman, Academic Press Inc., New York, 1952, vol. II, page 1174, basic methine dyes as described in British Pat. No. 462,238 and U.S. Pat. No. 2,164,793, basic azatrimethinecyanines dyes such as those disclosed by J. Voltz in Angew. Chem. (English edition) pp. 532537, October 1962; thiazole dyes such as Thioflavine T (C.I. 49,005); indamine basic dyes such as basic green C.I. 49,405; azine dyes such as Mauve (C.I. 50,245), Safranine T (C.I. 50,240), basic violet C.I. 50,055, basic blue C.I. 50,306, Induline 6B Base (C.I. 50,400); oxazine dyes such as basic blue C.I. 51,004, Mendolas Blue C.I. 51,175, basic black C.I. 51,215; thiazine dyes such as Methylene Blue C.I. 52,015, basic green C.I. 52,020; azo dyes such as the azosafranine dyes described in British Pat. No. 942,844 and U.S. Pat. No. 3,121,711, chrysoidine C.I. 11,270, basic brown C.I. 21,010, the basic azo dyes of British Pats. Nos. 808,713, 785,988, 896,681, 894,389, 459,594, 902,728 and U.S. Pat. Nos. 2,965,631; 3,020,272; 3,074,926; 3,033,847; 3,079,377; 2,099,525; 2,864,812; 2,864,813; 2,883,373; 2,889,315; 2,022,921; 2,238,485; 2,397,927; 2,906,747; 2,945,849; 3,096,318; 3,099,652 and 3,099,653; German Pat. Nos. 1,085,276; 1,088,631 and 1,135,589; French Pat. No. 1,295,862; anthraquinone dyes such as the basic violet mono and dicondensation products of quinizarin with 2-dimethylamino-ethylamine 0r 3-dimethylaminopropyl-amine (British Pat. No. 489,172), the basic dyes disclosed in U.S. Pat. 2,716,655, the basic dyes disclosed in U.S. Pat. 2,153,012, the basic dyes disclosed in U.S. Pats. 2,701,801 and 2,701,802, the basic dyes of U.S. Pats. 2,888,467; 2,611,722; 2,737,517; 2,924,609; and 3,076,821; Canadian Pat. 624,035; British Pats. 459,594; 807,214; 824,530; 903,007; 889,374 and 925,111; German Pats. 714,986; 1,073,129 and 1,082,916; French Pat. 1,277,495 and Belgian Pat. 609,667; nitro basic dyes such as those disclosed in U.S. Pats. 2,834,793 and 2,934,- 794; and basic quinophthalone dyes such as those disclosed in U.S. Pat. 3,023,212; Sevron Yellow 3RL (C.I. basic yellow 15), Sevron Orange G (C.I. basic orange 21), Sevron Brilliant Red 46 (C.I. basic red 14), Sevron Red GL (C.I. basic red 18), Sevron Blue B (C.I. basic blue 21), Sevron Blue 2G (C.I. basic blue 22), Sevron Green B (C.I. basic green 3), Astrazon Yellow 3G (C.I. basic yellow 11), Astrazon Blue BG (C.I. basic blue 3), Astrazon Blue 3RL (C.I. basic blue 47), Basacryl Yellow 5 GL (C.I. basic yellow 24), Basacryl Blue GL (C.I. basic blue 54), and Basacryl Blue 3RL (C.I. basic blue 53). Other suitable cationic dyes will be apparent to those skilled in the art.

In accordance with the present invention, the dyebath composition for dyeing shaped articles of acrylic polymers contains a cationic dye and an amount sufiicient to promote dyeing of methyl cyanide. Methyl cyanide (acetonitrile) is soluble in water. Therefore, no dispersing and/or suspending agents need be added to the dyebath. The methyl cyanide can be added to the dyebath in an amount of from about 0.5 to about 10 percent, preferably from about 1 to about 5, weight percent based on the weight of the total dyebath composition.

Fast color dyeing of acrylic articles generally can be performed by contacting the articles with an aqueous cationic dye-methyl cyanide containing dyebath for a time sufiicient to dye the articles. Generally, contact can be from about 1 to 3 hours at a temperature of from about C. to about C. Often, the dyebath can contain minor amounts of additives such as pH regulants, surface-active agents, etc., to assist in dyeing the articles. Dyeing of the acrylic articles with the dyebath composition of the present invention can be performed using dyeing procedures as will be apparent to those skilled in the art.

The following example is given as a specific illustration of the invention. It should be understood, however, that the invention is not limited to the specific details set forth in the example.

EXAMPLE An aqueous dyebath composition was prepared of 300 ml. water, mg. Sevron Blue B dye, 2 g./l. of sodium acetate, /2 g./l. of an alkylaryl polyether alcohol surfactant commercially available as Triton X-l02 and sufficient glacial acetic acid to achieve a pH of about 5.5. The sodium acetate is added to buffer the pH. Methyl cyanide was added to the dyebath in an amount of 3 ml. (0.78 weight percent of the total composition). A similar dyebath was prepared including 15 ml. of methyl cyanide (3.9 weight percent of the total composition). A third dyebath was prepared which was the same except that methyl cyanide was not added. The latter dyebath was used as a control sample.

Four acrylic fiber samples are added to each dyebath in an amount of 100 mg. of each fiber. Fiber A is a terpolymer of acrylonitrile, methylmethacrylate, and a minor quantity of sodium methallyl sulfonate. Fibers B, C and D are each acidic acrylonitrile-methylacrylate copolymer fibers. Fiber B is of American origin while fiber C is of Japanese manufacture and fiber D is of German manufacture. Each of the fibers is contacted in a closed can for 2 hours at 97 C. with the dyebath compositions containing 0, 0.78 and 3.9 percent by weight of the total composition of methyl cyanide. The fibers after dyeing are evaluated to determine the amount of dye in each fiber. The results, expressed as the weight percent of dye in each fiber for each dyebath composition are set forth in the table below.

TAB LE Dye in fiber, percent As may be seen from the table, the fibers which were contacted with the aqueous dyebath containing 0.78% by weight of the total composition of methyl cyanide surprisingly contained more dye than when they are contacted with an aqueous dyebath which contains 0 percent acetonitrile. The dye uptake resulting from contact with the 3.9 percent methyl cyanide-containing dyebath is even greater. These increases were found for every fiber sample. Sample D, for example, showed almost double the amount of dye at 3.9 percent methyl cyanide compared with the control sample. While the other fibers generally did not yield so dramatic an increase, the increase in uptake was substantial in every case. The data further indicates that when a predetermined amount of dye is desired in the fiber dyeing can be accomplished in a shorter time.

While the invention has been described with reference to the cationic dyeing, the methyl cyanide additive may also improve the dyeability of acrylic shaped articles with disperse or acidic dyes where the articles are otherwise dyeable with these types of dyes. The invention may be particularly applicable with highly drawn or industrial acrylic fibers or those having very low dye site concentrations.

Although the invention has been described with preferred embodiments, it is to be understood that variations and modifications may be resorted to as will be apparent to those skilled in the art. Such variations and modifications are to be considered within the purview and scope of the claims appended thereto.

1 claim:

1. An improved composition suitable for dyeing polymers of acrylonitrile comprising:

(a) an aqueous dyebath of a cationic dye, and

(b) from about 0.5 to about percent by weight based upon the weight of the total composition of methyl cyanide.

2. The improved composition of claim 1 wherein the acrylic shaped articles contain not less than about mol percent of acrylonitrile units and not more than about 15 mol percent of units derived from a monovinyl compound polymerizable with acrylonitrile.

3. The improved composition of claim 1 wherein said methyl cyanide is present in said improved composition in a quantity of from about 1 to about 5 percent by weight based upon the weight of the total composition.

4. An improved process for dyeing polymers of acrylonitrile which comprises contacting the polymers of acrylonitrile to be dyed with an aqueous dyebath comprising:

(a) a cationic dye, and

(b) from about 0.5 to about 10 percent by weight based upon the weight of the total composition of methyl cyanide.

5. An improved process for dyeing acrylic shaped article in accordance with claim 4 wherein said acrylic shaped article is a fiber.

6. An improved process for dyeing an acrylic shaped article in accordance with claim 4 wherein said acrylic shaped article is a film.

7. An improved process in accordance with claim 4 wherein said acrylic shaped article contains not less than about 85 mol percent of acrylonitrile units and not more than about 15 mol percent of units derived from a monovinyl compound polymerizable with acrylonitrile.

S. The method of claim 4 wherein said methyl cyanide is present in said improved composition in a quantity of from about 1 to about 5 percent by weight based upon the weight of the total composition.

References Cited UNITED STATES PATENTS 3,565,572 2/1971 Schneider et a1. 8-l72 X 2,888,314 5/1959 Matlin et al. 8l72 X 3,114,588 12/1963 Lewis 893 3,493,981 2/1970 Noda et a1. 8-172 LEON D. ROSDOL, Primary Examiner T. J. HERBERT, 1a., Assistant Examiner US. Cl. X.R. 8-83, 177 AB 

